/* global PhotoSwipe, PhotoSwipeUI_Default */
var initPhotoSwipeFromDOM = function (gallerySelector) {
  // parse slide data (url, title, size ...) from DOM elements
  // (children of gallerySelector)
  var parseThumbnailElements = function (el) {
    var thumbElements = el.childNodes
    var numNodes = thumbElements.length
    var items = []
    var figureEl
    var $figureEl
    var $lightboxHtmlElement
    var linkEl
    var size
    var item

    for (var i = 0; i < numNodes; i++) {
      figureEl = thumbElements[i] // <figure> element
      $figureEl = $(figureEl)

      // We only allow <figure> html elements
      if ($figureEl.prop('nodeName') !== 'FIGURE') {
        continue
      }

      // include only element nodes
      if (figureEl.nodeType !== 1) {
        continue
      }

      linkEl = figureEl.children[0] // <a> element

      size = linkEl.getAttribute('data-size').split('x')

      // create slide object
      $lightboxHtmlElement = $figureEl.find('[data-lightbox=html]')
      if ($lightboxHtmlElement.length === 1) {
        item = {
          'html': $lightboxHtmlElement.html(),
          'el': figureEl
        }
        items.push(item)

        continue
      }

      item = {
        src: linkEl.getAttribute('href'),
        w: parseInt(size[0], 10),
        h: parseInt(size[1], 10)
      }

      if (figureEl.children.length > 1) {
        // <figcaption> content
        item.title = figureEl.children[1].innerHTML
      }

      if (linkEl.children.length > 0) {
        // <img> thumbnail element, retrieving thumbnail url
        item.msrc = linkEl.children[0].getAttribute('src')
      }

      item.el = figureEl // save link to element for getThumbBoundsFn
      items.push(item)
    }

    return items
  }

  // find nearest parent element
  var closest = function closest (el, fn) {
    return el && (fn(el) ? el : closest(el.parentNode, fn))
  }

  // triggers when user clicks on thumbnail
  var onThumbnailsClick = function (e) {
    e = e || window.event
    e.preventDefault ? e.preventDefault() : e.returnValue = false

    var eTarget = e.target || e.srcElement

    // find root element of slide
    var clickedListItem = closest(eTarget, function (el) {
      return (el.tagName && el.tagName.toUpperCase() === 'FIGURE')
    })

    if (!clickedListItem) {
      return
    }

    // find index of clicked item by looping through all child nodes
    // alternatively, you may define index via data- attribute
    var clickedGallery = clickedListItem.parentNode
    var childNodes = clickedListItem.parentNode.childNodes
    var numChildNodes = childNodes.length
    var nodeIndex = 0
    var index

    for (var i = 0; i < numChildNodes; i++) {
      // We only allow <figure> html elements
      if ($(childNodes[i]).prop('nodeName') !== 'FIGURE') {
        continue
      }

      if (childNodes[i].nodeType !== 1) {
        continue
      }

      if (childNodes[i] === clickedListItem) {
        index = nodeIndex
        break
      }
      nodeIndex++
    }

    if (index >= 0) {
      // open PhotoSwipe if valid index found
      openPhotoSwipe(index, clickedGallery)
    }
    return false
  }

  // parse picture index and gallery index from URL (#&pid=1&gid=2)
  var photoswipeParseHash = function () {
    var hash = window.location.hash.substring(1)
    var params = {}

    if (hash.length < 5) {
      return params
    }

    var vars = hash.split('&')
    for (var i = 0; i < vars.length; i++) {
      if (!vars[i]) {
        continue
      }
      var pair = vars[i].split('=')
      if (pair.length < 2) {
        continue
      }
      params[pair[0]] = pair[1]
    }

    if (params.gid) {
      params.gid = parseInt(params.gid, 10)
    }

    return params
  }

  var openPhotoSwipe = function (index, galleryElement, disableAnimation, fromURL) {
    var pswpElement = document.querySelectorAll('.pswp')[0]
    var gallery
    var options
    var items = parseThumbnailElements(galleryElement)

    // define options (if needed)
    options = {

      // define gallery index (for URL)
      galleryUID: galleryElement.getAttribute('data-pswp-uid'),

      getThumbBoundsFn: function (index) {
        // See Options -> getThumbBoundsFn section of documentation for more info
        var thumbnail = items[index].el.getElementsByTagName('img')[0] // find thumbnail
        var pageYScroll = window.pageYOffset || document.documentElement.scrollTop
        var rect = thumbnail.getBoundingClientRect()

        return {x: rect.left, y: rect.top + pageYScroll, w: rect.width}
      }

    }

    // PhotoSwipe opened from URL
    if (fromURL) {
      if (options.galleryPIDs) {
        // parse real index when custom PIDs are used
        // http://photoswipe.com/documentation/faq.html#custom-pid-in-url
        for (var j = 0; j < items.length; j++) {
          if (items[j].pid === index) {
            options.index = j
            break
          }
        }
      } else {
        // in URL indexes start from 1
        options.index = parseInt(index, 10) - 1
      }
    } else {
      options.index = parseInt(index, 10)
    }

    // exit if index not found
    if (isNaN(options.index)) {
      return
    }

    if (disableAnimation) {
      options.showAnimationDuration = 0
    }

    // Pass data to PhotoSwipe and initialize it
    gallery = new PhotoSwipe(pswpElement, PhotoSwipeUI_Default, items, options)
    gallery.init()
  }

  // loop through all gallery elements and bind events
  var galleryElements = document.querySelectorAll(gallerySelector)

  for (var i = 0, l = galleryElements.length; i < l; i++) {
    galleryElements[i].setAttribute('data-pswp-uid', i + 1)
    galleryElements[i].onclick = onThumbnailsClick
  }

  // Parse URL and open gallery if it contains #&pid=3&gid=1
  var hashData = photoswipeParseHash()
  if (hashData.pid && hashData.gid) {
    openPhotoSwipe(hashData.pid, galleryElements[hashData.gid - 1], true, true)
  }
}

/**
 * MediaLibrary lightbox
 */
jsFrontend.mediaLibraryLightbox = {
  init: function () {
    // when no items for lightbox found, stop here
    if ($('.widget-media-library-lightbox').length === 0) {
      return false
    }

    // init lightboxes
    initPhotoSwipeFromDOM('.widget-media-library-lightbox')
  }
}

$(jsFrontend.mediaLibraryLightbox.init)
